The present invention relates to a new and improved construction of apparatus for the infeed of printed products or the like to a stacker, comprising an endless revolving conveyor, the outfeed portion of which is elevationally adjustable and automatically accommodatable to the height of the formed stack. While the invention will be described by way of example in conjunction with the handling of printed products, it obviously can be used with other usually flat articles.
According to a prior art apparatus of this type the conveyor is constructed as a conveyor band or belt mounted in a rocker arm or balance which, in turn, is pivotable about a shaft arranged at the region of the infeed or inlet of the conveyor band. At the region of the end of the rocker arm or balance there is arranged the outfeed portion of the conveyor band and an arm which engages over the stack and bears upon the top side thereof, so that the height of the outfeed portion of the conveyor band automatically remains accommodated to the height of the growing stack. With this equipment, by changing the height of its delivery or outfeed location, there is taken into account the increasing height of the stack, in contrast to other equipment where the support surface of the stack is lowered as a function of its increasing size or growth.
Although with the heretofore known equipment this elevational adjustment of the outfeed portion is especially simple and, without any particular measures, also is automatically accommodated to different rates of growth of the stack, for practical reasons there is limited the elevational range which this outfeed portion is able to cover, and hence, there is equally limited the maximum attainable stack-height within the stacker. This is so because during rocking of the rocker arm or balance the outfeed portion of the conveyor band describes an arc and additionally, because the change in slope of the conveyor band, occurring during the course of the elevational adjustment, is limited to relatively narrow ranges.
Therefore, if there is to be infed articles to a stacker with the heretofore known equipment, and which stacker is constructed for forming particularly high stacks i.e. for instance having a height of 1 meter and more, then the length of the conveyor band and thus the rocker arm must be considerably increased in size, in order that the outfeed portion of the conveyor band can cover the elevational range of the stack without the band exceeding that limit of the slope which has been determined by experience. An extension of the rocker arm, however, apart from the increased technological expenditure, constitutes an increased spatial requirement at the place of erection of the equipment.
On the other hand, due to the considerably increased production capacity, for instance in the case of modern day rotary printing presses, there exists the tendency of providing stackers capable of handling increasingly greater stack heights. This development has been clearly documented, for instance, by the stackers disclosed in Swiss Pat. No. 566,928 and especially German patent publication No. 2,518,374. In reality, these stackers are designed such that they are capable of forming stacks which in their height far exceed heretofore conventionally formed stacks.